Minutes from the October 9, 2019 IBIS Interconnect Task group meeting are
attached.
Regards,
Justin
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IBIS INTERCONNECT TASK GROUP
http://www.ibis.org/interconnect_wip/ ;
Mailing list: ibis-interconnect@xxxxxxxxxxxxx
Archives at //www.freelists.org/archive/ibis-interconn/ ;
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Attendees from October 9, 2019 Meeting (* means attended at least using audio)
ANSYS Curtis Clark
Cadence Design Systems Bradley Brim
Intel Corp. Michael Mirmak*
Keysight Technologies Radek Biernacki
Mentor, A Siemens Business Arpad Muranyi*
Micron Technology Justin Butterfield*, Randy Wolff*
SiSoft Walter Katz, Mike LaBonte*
Teraspeed Labs Bob Ross*
Michael Mirmak convened the meeting. No patents were declared.
Justin Butterfield took minutes.
Review of Minutes:
- Michael called for review of the minutes from the October 2, 2019 meeting.
Randy Wolff moved to approve the minutes. Bob Ross seconded. The minutes
were approved without objection.
Review of ARs:
- Walter Katz to go through Bob's changes and accept the changes he approves of
and
send out draft 22.
- Michael reported draft 22 was sent out.
- Randy to create a stacked die EMD model with power rails.
- Randy reported this is started. We can review this, but he has some
questions
on how to proceed with some of the syntax.
Opens:
- None.
Stacked Die EMD Example:
Randy noted he started with a full package spice model with terminals at three
different locations, including the package BGA balls and the die pads at each
of the
two die. The power and ground rails are merged to single terminals at each of
these locations. Randy added an additional EMD Group for the fully coupled
model.
He was not sure if he wanted to include the decoupling capacitance. Randy did
not
put in the EMD model terminals, yet as he has some questions on how to connect
the
rails. Michael asked if the question is only on the rails. Randy replied the
syntax for the signals is clear and these are straightforward to connect. For
rails, he wants every instance of the VDD pin to be shorted to a single VDD
terminal. In the syntax, we have only shown this being done with pin_names
separated by commas, which in this case would be a very long list.
Bob noted this gets back to the connected and shorted discussion. For IO pins,
the
model maker may not want these shorted but they have the same signal_name.
Arpad
Muranyi agreed there might be places where we want an ideal short. Bob did not
want
to apply shorts across different devices. Randy noted we want to have a way to
define terminals, but he does not want to have to define all the terminals in a
long
list. Another method could be signal_name or we could use bus_label to define
the
rail connections. Arpad asked if we are reaching into the component and
looking at
the signal_names. Randy commented the EMD is doing the mapping and we should
not be
going inside the IBIS file and looking at the component. The signal_names or
bus_labels need to be defined in the EMD. Arpad asked how we would resolve
differences between the EMD and IBIS rail connections. Bob suggested to have
the
higher level take priority, or the pins determine the connectivity. Arpad
suggested
to write rules for this.
Arpad asked about the merged pins syntax for package models and if we can
achieve
this same functionality with the current EMD syntax. Randy replied that this
is
what he is having trouble defining as he cannot short terminals as he would
like.
Arpad asked if rail pins can be left as opens in this syntax. Randy stated
this
could be done with bus_label, or signal_name could be used to merge all the
pins.
Bob noted we could leave some of the pins out of the list of pins, but he has
concerns with this, since you have to list the pin_names with no information on
the
signal_names. Arpad noted for board simulations you need to know what pins to
connect the model. Randy commented the resolution of the models for the board
and
the component may be different. Arpad noted that the component model may only
define only one pin for an entire rail. He was concerned that the merged pin
syntax
allows for these cases, but the EMD syntax does not.
Michael asked if the syntax does not exist to do what we want. Randy replied
the
syntax does not exist to have a signal_name connection. This would be useful
for
connecting rails, as he does not want to list a bunch of pin_names. Bob noted
that
the grouping is based on the board model and not the models of the components.
Arpad commented the merged pin syntax is not supported for these EMD models.
Bob
commented that some of this functionality can be replicated with bus_label.
Arpad was concerned about getting conflicting information from the EMD and the
component. Bob commented the connections are made by the pins. Arpad asked
what
happens if the EMD tells the tool to connect the pins and the component tells
the
tool to connect other pins. And, what happens if there is a mistake. Randy
noted
that the model maker could make mistakes, but he was not sure if this would be
checkable. Michael asked if we would need additional information for the
syntax to
work. Bob stated we can look inside the component, but we have chosen not to.
Arpad commented that the spec should define how to make the connections and
when to
leave things open with similar functionality to the merged pins BIRD. Bob was
concerned this would complicate the syntax.
Randy suggested to add some simple rules about the meaning of the syntax.
Michael
asked if Randy can draft some statements on these rules. Randy to propose some
rules for the merged pin cases [AR].
Arpad to present a review of the merged pin syntax issue [AR]. Bob commented
that
merged pins interact with pin mapping and bus_label.
Next Meeting:
The next meeting will be October 16.
Mike LaBonte moved to adjourn. Arpad seconded. The meeting adjourned without
objection.
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Bin List:
EMD Comments to be Resolved:
1. Should the [Define Module] keyword be renamed? - RESOLVED
2. Documentation of CAD nets, extended nets and signal names definitions. -
RESOLVED
3. Add bus_labels as possible Terminal_type_qualifiers. - RESOLVED
4. Add [End EMD Pin List], [End Designator Pin List] to keyword hierarchy. -
RESOLVED
5. Remove [Number of EMD Pins] keyword? - CLOSED
6. Add definition of "Nyquist". - CLOSED
IBIS-ISS Parser:
- IBIS-ISS parser scope document
